20021131121 has 4 divisors (see below), whose sum is σ = 20219360244. Its totient is φ = 19822902000.

The previous prime is 20021131093. The next prime is 20021131133. The reversal of 20021131121 is 12113112002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11264850496 + 8756280625 = 106136^2 + 93575^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021131121 - 2¹⁸ = 20020868977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021131096 and 20021131105.

It is not an unprimeable number, because it can be changed into a prime (20021131181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99114410 + ... + 99114611.

It is an arithmetic number, because the mean of its divisors is an integer number (5054840061).

Almost surely, 2^20021131121 is an apocalyptic number.

It is an amenable number.

20021131121 is a deficient number, since it is larger than the sum of its proper divisors (198229123).

20021131121 is a wasteful number, since it uses less digits than its factorization.

20021131121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198229122.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 20021131121 its reverse (12113112002), we get a palindrome (32134243123).

The spelling of 20021131121 in words is "twenty billion, twenty-one million, one hundred thirty-one thousand, one hundred twenty-one".